Micropump and adhesive-free method for joining two substrates

ABSTRACT

The invention relates to a device provided with channel-type structures for transporting and/or storing a liquid and/or gaseous medium. The device comprises a first ( 1 ) substrate layer and a second substrate layer ( 2 ), and a functional element ( 3 ) that is sandwiched between the first and second substrate layers, the channel-type structures being embodied in the first and/or second substrate layer. The first and second substrate layers are solidly and permanently interconnected, and the functional element is clamped between the first and second substrate layers. The functional element is elastic, the first and second layers are rigid, and the channel-type structures in the first and/or second substrate layers are at least partially sealed in a gas-tight and/or liquid-tight manner due to the functional element.

The present invention relates to an adhesive-free method for joining twosubstrates and in particular to a micropump which has been produced inparticular by means of the adhesive-free method for joining twosubstrates.

The prior art has disclosed a wide range of methods for joining a first,second and third substantially two-dimensional layer in particular madefrom plastic and/or glass and/or substrate and/or metal to one another.By way of example, the first, second and third layers can be joined toone another by means of adhesives, in which case the methods which areknown from the prior art in each case use three layers which are ofsubstantially equal size in terms of the extent of their area.

Moreover, the prior art has disclosed micropumps which substantiallycomprise a housing lower part and a housing upper part, between whichthere is arranged a valve diaphragm, cf. for example DE-19720482 C2.

The methods for joining three layers which are known from the prior artare generally very complex and expensive, and this equally also appliesto the micropumps which are known from the prior art and are produced bythe said methods.

Therefore, it is an object of the present invention to provide amicropump of compact design with a high pumping capacity which can beproduced even in large numbers using simple and inexpensive productionand joining techniques. A further object of the present invention is toprovide an inexpensive method for producing a micromechanical componentwhich substantially comprises a two-layer structure with a functionalelement between the two layers.

The objects are achieved by the features of the independent claims.Advantageous embodiments of the present invention are described in thesubclaims and/or the following description, which is accompanied bydiagrammatic drawings, in which:

FIGS. 1 a, b, c and d diagrammatically depict the basic elements of anapparatus according to the invention;

FIGS. 2 a, b and c each show modifications to the apparatus according tothe invention shown in FIG. 1;

FIG. 3 a shows a diagrammatic plan view of the main components of anapparatus according to the invention in accordance with a firstembodiment of the present invention, and FIG. 3 b shows a sectionthrough components from FIG. 3 a arranged on top of one another;

FIG. 4 a shows a partial section through components of an apparatusaccording to the invention, arranged on top of one another, inaccordance with a second embodiment of the present invention, and FIGS.4 b and c show diagrammatic plan views of a functional element of thesecond embodiment of the present invention from FIG. 4 a;

FIG. 5 a shows a diagrammatic partial section through components of anapparatus according to the invention, arranged on top of one another, inaccordance with a third embodiment of the present invention, and FIGS. 5b and 5 c show diagrammatic plan views of a functional element of thethird embodiment of the present invention from FIG. 5 a;

FIG. 6 a diagrammatically depicts the arrangement of an apparatusaccording to the invention in accordance with a fourth embodiment of thepresent invention, and FIG. 6 b diagrammatically depicts a functionalelement of a fourth embodiment of the present invention from FIG. 6 a,and FIG. 6 c diagrammatically depicts the arrangement of an apparatusaccording to the invention in accordance with a fifth embodiment of thepresent invention, and FIG. 6 d diagrammatically depicts a functionalelement of a fifth embodiment of the present invention from FIG. 6 c.

FIGS. 7 a and 7 b show further diagrammatic illustrations, in the formof an exploded view and in section, respectively, of an apparatusaccording to the invention in accordance with the first embodiment ofthe present invention from FIG. 3.

FIG. 8 shows an advantageous modification to the functional elementshown in FIG. 6 d.

FIG. 9 shows a diagrammatic section through an apparatus according tothe invention in the arrangement from FIG. 6 c.

FIG. 10 shows an advantageous modification to the apparatus according tothe invention from FIG. 9.

The present invention is based on the idea of providing a method forjoining a first substrate layer 1, a second substrate layer 2 and afunctional element 3, with the functional element 3 being elastic inform and/or being designed to be very much thinner than the firstsubstrate layer 1 and the second substrate layer 2, and the functionalelement being arranged in sandwich fashion between the first substratelayer 1 and the second substrate layer 2, and the first layer 1 andsecond layer 2 being joined together by means of pressure, so that thefunctional element 3 is clamped between the two layers in such a mannerthat the first layer 1 and second layer 2 are permanently joined to oneanother and the functional element 3 is arranged permanently between thefirst layer 1 and the second layer 2. In this case, the first layer 1and the second layer 2 and the functional element 3 are substantiallytwo-dimensional in form, with the functional element 3 according to theinvention having a smaller surface area than the first layer 1 one andthe second layer 2.

According to the invention, in this case the pressure and the materialof layer 1 and layer 2 are selected in such a manner that layer 1 andlayer 2 are permanently joined to one another after the pressure hasbeen removed.

Moreover, the method according to the invention comprises in particularthe following steps, in which first of all the functional element 3 isarranged at a predetermined position on one of the layers 1 or 2, forexample on the layer 1, and then a suitable solvent is applied to thesurface of the layer 1 or 2 which is not covered by the functionalelement 3, and then the second layer 2 is arranged above the first layer1 and the functional element 3, and then pressure is exerted on thesecond layer 2, so that the first layer 1 and second layer 2 are joinedto one another and the functional element 3 is clamped between thelayers 1 and 2.

According to the invention, in this case the material of the layers 1and 2 and the solvent and the level and duration of the pressure areselected in such a manner that after the pressure has been removedlayers 1 and 2 are permanently joined to one another.

It is appropriate for the functional element to comprise a thin plasticfilm and/or a metal foil.

The first layer 1 and second layer 2 expediently comprise a substratelayer made from plastic and preferably from polycarbonate and/or PPSUand/or PEI and/or melamine.

A parallel basic concept of the present invention is to provide anapparatus with channel-like structures for transporting and/or storing aliquid and/or gaseous medium, which comprises a first substrate layer 1and a second substrate layer 2, between which is arranged a functionalelement 3 which is elastic in form and/or designed to be very muchthinner than the first layer 1 and the second layer 2, with thechannel-like structures being formed in the first layer 1 and/or thesecond layer 2, and the first layer 1 and the second layer 2 beingfixedly and permanently joined to one another, and the functionalelement 3 being clamped between the first layer 1 and the second layer2, so that the channel-like structures in the first layer 1 and/or thesecond layer 2 are at least partially closed off in a gastight and/orliquid-tight manner by means of the functional element 3.

An apparatus according to the invention comprises in particular afunctional element 3 which is designed as a movable element, in such amanner that a channel-like structure in the first layer 1 and/or secondlayer 2 can be opened and/or closed by means of the functional element3, it being possible for the functional element 3 in particular to havea valve function.

An apparatus according to the invention expediently provides amicropump, in which case the functional element 3 includes at least onevalve flap 31 and the apparatus moreover comprises a dynamic driveelement 4 which is suitable for altering the volume of a cavity formedin the apparatus.

An apparatus according to the invention expediently comprises a firstlayer 1, in which a first channel 10 is formed, and a second layer 2, inwhich a second channel 20 is formed, so that a connection is producedbetween the first channel 10 and the second channel 20. Moreover, avalve flap 31 of the functional element 3 is arranged in such a mannerthat the connection between the first channel 10 and the second channel20 is opened or closed. In an apparatus according to the invention, inparticular and expediently the first channel 10 and second channel 20are arranged substantially parallel, in which case the connectionbetween the first channel 10 and second channel 20 includes an angle αfrom 5° to 80°, preferably from 15° to 50°, with the first channel 10and second channel 20, so that a tangential transition between the firstchannel 10 and second channel 20 is provided by means of the connectionbetween the first channel 10 and second channel 20. Moreover, the valveflap 31 of the functional element 3 is expediently arranged at thelocation of the connection between the first channel 10 and secondchannel 20.

In particular and expediently, the first channel 10 has a first width 10b′, the second channel 20 has a second width 20 b′ and the valve flap31′ has a third width 31 b′, in which case the first width 10 b′<thirdwidth 31 b′<second width 20 b′, and in which case a drive element 4, asseen in the direction of flow F, is connected upstream (4, 132) and/ordownstream (132, 4) of the valve flap 31′, thereby providing a pumpstructure (I).

According to a modified embodiment of the present invention, inparticular and expediently an apparatus is provided having a firstchannel 10 with a first width 10 b″, a second channel 20 with a secondwidth 20 b″ and a valve flap 31″ with a third width 31 b″, in which casethe second width 20 b″<the third width 31 b″<the first width 10 b″, andin which case a drive element 4 is connected upstream (4, 231) and/ordownstream (231, 4) of the valve flap 31″, as seen in the direction offlow F, thereby providing a pump structure (II) according to theinvention.

According to the invention, a multiplicity of micropump structures (I)and/or (II) may be formed in combination in an apparatus according tothe invention. In particular and expediently, an apparatus according tothe invention comprises a central drive element 4, with at least onefirst valve flap 31′, in accordance with pump structure (I), connectedupstream (4, 132) of it, as seen in the direction of flow F, andmoreover with at least one second valve flap 31″, in accordance withpump structure (II), connected downstream (231, 4) of it, as seen in thedirection of flow (F), and an apparatus according to the invention alsocomprises in particular a third valve flap 31′, in accordance with pumpstructure I, which is connected downstream (132, 4) of the drive element4, as seen in the direction of flow F, and is connected upstream of thesecond valve flap 31″, and moreover a fourth valve flap 31″, inaccordance with pump structure II, which is connected upstream (231, 4)of the drive element 4, as seen in the direction of flow F, and isconnected downstream of the first valve flap 31′. In this case, inparticular and expediently the valve flaps 31′ and 31″ are formed inthis arrangement in the direction of flow in a plastic film 3, andmoreover a recess 30, which is connected to a cavity interacting withthe drive element 4, is formed between the third and fourth valve flaps31′ and 31″.

According to one particularly advantageous embodiment of the presentinvention, an apparatus according to the invention comprises a seriesconnection of pump structures (I), (II), (I) and (II) with an associatedfirst 31′, second 31″, third 31′ and fourth 31″ valve flap in this orderin the direction of flow, with a central drive element 4 and a cavity(pump chamber) arranged between the middle pump structures (II) and (I).In this case, in particular and expediently the valve flaps 31′ and 31″are formed in this arrangement in the direction of flow in a functionalelement 3. Moreover, a recess 30, which interacts with the pump chamberand the drive element 4, is formed between the two middle valve flaps31′ and 31″.

According to one particularly advantageous embodiment of the presentinvention, an apparatus according to the invention comprises a seriesconnection of pump structures (I), (II), (I) and (II) with an associatedfirst, second, third and fourth valve flap 31 in this order in thedirection of flow, with a central drive element 4 and a cavity (pumpchamber) arranged between the middle pump structures (II) and (I). Inthis case, in particular and expediently the valve flaps 31 are formedin this arrangement in the direction of flow in a functional element 3.Moreover, a recess 30, which interacts with the pump chamber and thedrive element 4, is formed between the two middle valve flaps 31.

According to an advantageous embodiment of the functional element 3according to the invention, a hole structure 30′ with a filter actionmay be provided instead of the recess 30, in which case the functionalelement 3 is expediently formed in a thin plastic film.

The text which follows provides a detailed description of advantageousembodiments of the present invention with reference to the accompanyingdrawings.

FIGS. 1 a, b, c and d diagrammatically depict the basic elements of anapparatus according to the invention; these figures also illustrate theunderlying principle of the method according to the invention. In themethod according to the invention for joining a first substrate layer 1,a second substrate layer 2 and a functional element 3 which is elasticin form and is expediently designed to be very much thinner than thefirst substrate layer 1 and second substrate layer 2. Moreover, thefunctional element 3 is arranged in sandwich fashion between the firstsubstrate layer 1 and second substrate layer 2, the functional element 3having a smaller surface area than the first layer 1 and second layer 2and expediently being arranged at a predetermined position on the firstsubstrate layer 1. Then, a suitable solvent is applied to the surface ofthe substrate layer 1 which is not covered by the functional element 3.Then, the second substrate layer 2 is arranged above the first layer 1and the functional element 3 and pressure is exerted on the secondsubstrate layer 2, so that the first substrate layer 1 and secondsubstrate layer 2 are joined and the functional element 3 is clampedbetween the substrate layers 1 and 2, with the result that the firstsubstrate layer 1 and second substrate layer 2 are permanently joined toone another and the functional element 3 is arranged permanently betweenthe first substrate layer 1 and the second substrate layer 2.

In this case, the material of substrate layers 1 and 2 and the solventand the level and duration of the pressure are selected in such a mannerthat layers 1 and 2 are permanently joined to one another after thepressure has been removed.

As is diagrammatically depicted in FIGS. 1 c and d, positioningrecesses, which interact with positioning pins on the functional element3, may be formed in the first substrate layer 1, so that the functionalelement 3 can easily and accurately be arranged at a predeterminedposition on the substrate layer 1. It will be clear that conversely itis also possible for positioning pins to be formed on the surface of thefirst substrate layer 1 and positioning recesses or positioning holeswhich interact with the positioning pins of the substrate layer 1 to beformed on the functional element 3.

According to the invention, the functional element 3 is substantially inthe form of a two-dimensional layer which is elastic in form andexpediently designed to be very much thinner than the first substratelayer 1 and second substrate layer 2, and moreover the functionalelement 3 has a smaller surface area than the first substrate layer 1and second substrate layer 2, and furthermore the first substrate layer1 and second substrate layer 2 are formed from a material which can bejoined by means of a suitable solvent and pressure and moreover has asufficient elasticity for it to be possible for the functional element 3to be clamped between the first substrate layer 1 and second substratelayer 2 by means of pressure while the surfaces of the first substratelayer 1 and second substrate layer 2 are in contact with and joined toone another and are permanently joined to one another after the pressurehas been removed. In this case, the functional element 3 can be clampedbetween the two substrate layers 1 and 2 in such a manner that nocavities x are formed at its edges.

It is expedient for the first substrate layer 1 and second substratelayer 2 to be formed from plastic and preferably from polycarbonateand/or PPSU and/or PEI and/or melamine, and the functional element 3 isexpediently a thin plastic film and/or a metal foil and is in particularformed from plastic and preferably from a polyimide.

FIGS. 2 a, b and c diagrammatically depict the basic elements of anapparatus according to the invention and in each case modifications tothe apparatus according to the invention shown in FIG. 1. In theapparatus in accordance with FIG. 2 a, by way of example two functionalelements 3 are clamped between a first substrate layer 1 and a secondsubstrate layer 2, in which context it will be clear that according tothe invention it is also possible for a multiplicity of functionalelements 3 to be clamped between a first substrate layer 1 and a secondsubstrate layer 2 by means of the method according to the invention.

FIG. 2 b shows the basic components of a further modification to theapparatus according to the invention shown in FIG. 1; in this figure, byway of example, only one functional element 3 is clamped between a firstsubstrate layer 1 and a second substrate layer 2. Moreover, in theembodiment shown in FIG. 2, the first substrate layer 1 is pretreated insuch a manner, i.e. a suitable recess formed in the surface of substratelayer 1, that the functional element 3 can be arranged in an accurateposition in the recess. Moreover, in the embodiment shown in FIG. 2 b,it is possible for the functional element 3 to be thicker than afunctional element 3 of the embodiment shown in FIG. 1 and FIG. 2 a. Thefunctional element 3 of the embodiment shown in FIG. 2 b expediently hasa thickness which is greater than or equal to the depth of the recess inthe substrate layer 1.

FIG. 2 c diagrammatically depicts the main components of a furthermodification to an apparatus according to the invention, in which case asuitable recess is formed in the second substrate layer 2 as well, in acorresponding position to the recess in the substrate layer 1 and thefunctional element 3. In the embodiment shown in FIG. 2 c, thefunctional element 3 may have a greater thickness than the functionalelement 3 of the embodiments shown in FIGS. 1, 2 a and 2 b, in whichcase the thickness of the functional element 3 is expediently greaterthan or equal to the sum of the depths of the recesses in the substratelayers 1 and 2.

It will be clear that further modifications to an apparatus according tothe invention and the method according to the invention can also beprovided by combinations of the embodiments shown in FIGS. 1, 2 a, 2 band 2 c.

The following figures diagrammatically depict the main components of anapparatus according to the invention in accordance with furtherembodiments of the present invention, with a basic arrangement of theembodiment shown in FIG. 1 having been selected, in which there are norecesses for positioning the functional element 3 formed in the twoopposite substrate layers 1 and 2. It will be clear that the embodimentsdescribed below can also be provided in a corresponding form to theembodiments of FIGS. 2 b or 2 c described above and that the respectivefunctional elements 3 and/or substrate layers 1 and/or 2 may also havepositioning formations as described with reference to FIG. 1 and 2.

FIG. 3 a shows a plan view of the main components of an apparatusaccording to the invention in accordance with a first embodiment of thepresent invention, and FIG. 3 b shows a section through components ofFIG. 3 a arranged on top of one another.

The first embodiment of the present invention as shown in FIG. 3 aprovides an apparatus having channel-like structures for transportingand/or storing a liquid and/or gaseous medium, the apparatus comprisinga first substrate layer 1 and a second substrate layer 2 and afunctional element 3 which is elastic in form and is expedientlydesigned to be very much thinner than the first substrate layer 1 andsecond substrate layer 2 and which is arranged in sandwich fashionbetween the first substrate layer 1 and second substrate layer 2.Moreover, channel-like structures 10 and 20 are formed in the firstsubstrate layer 1 and/or the second substrate layer 2, and the firstsubstrate layer 1 and second substrate layer 2 are fixedly andpermanently joined to one another, with the functional element 3 beingclamped between the first substrate layer 1 and second substrate layer 2in such a manner that the channel-like structures 10 and 20 in the firstsubstrate layer 1 and/or second substrate layer 2 are closed off atleast in a gastight and/or liquid-tight manner by means of thefunctional element 3. According to the invention, in the embodimentshown in FIG. 3, a channel 10 which is open at the top is formed in thefirst layer 1, and a continuous opening 20 which passes all the waythrough the layer 2 and interacts with the channel 10 is formed in thesecond layer 2. Moreover, according to the invention the functionalelement 3 is designed as a thin film with a through-opening 30 whichinteracts with the opening 20 in the second substrate layer 2, and isalso designed with a valve flap 31, the width and length of whichcorrespond to the width and depth of the channel 10.

According to the invention, the layers 1 and 2 are now arranged oneabove the other, and moreover the functional element 3 is arranged insandwich fashion between the substrate layers 1 and 2, in such a mannerthat the channel 10 is connected to a cavity interacting with a driveelement 4 by means of the opening 30 and 20, and moreover the channel 10can be opened and/or closed by means of the valve flap 31, so as toprovide a pump structure according to the invention.

The pump structure described above is diagrammatically depicted in FIG.3 b. The drive element 4 may, for example and expediently, be providedby means of a piezo actuator 4. In the embodiment shown in FIG. 3 b, byway of example, the opening 30 and 20 and the drive element 4 areconnected downstream of the valve flap 31 as seen in the direction offlow (arrow direction). It will be clear that the opening 20 and 30 andthe drive element 4, given a suitable design of the valve flap 31, mayalso be connected upstream of the latter as seen in the direction offlow, and/or in each case second openings 20 and 30 in addition to theopenings 20 and 30 shown in FIGS. 3 a and 3 b and a second drive element4 in addition to the drive element 4 connected downstream of the valveflap 31 may be connected upstream of the valve flap 31.

Expediently and advantageously, it is also possible for a hole structure30′, which has a filter action and effectively prevents anycontaminating or dirt particles contained in a liquid that is to bepumped from entering the cavity or the pump chamber, to be formed in thefunctional element 3 instead of the opening 30. An advantageous holestructure 30′ of this type is diagrammatically depicted in FIG. 8 and isdescribed in more detail below.

FIG. 4 a shows a partial section through components of an apparatusaccording to the invention, arranged on top of one another, inaccordance with a second embodiment of the present invention, and FIG. 4b shows a plan view and FIG. 4 c a partial plan view of a functionalelement of the second embodiment of the present invention from FIG. 4 a.

The second embodiment of the present invention as shown in FIG. 4substantially corresponds to the embodiment shown in FIG. 3, except thatthe channel 10 in the first layer shallows out at a predeterminedposition with a predetermined angle α, and moreover a second channel 20,which likewise shallows out at a predetermined position and at apredetermined angle α and interacts with the channel 10 formed in thefirst substrate layer 1 in such a manner that when the substrate layers1 and 2 are arranged on top of one another a tangential connectionbetween the channels 10 and 20 at a predetermined angle α is provided,is formed in the second substrate layer 2. Moreover, the channel 20 isdesigned in such a manner that at a predetermined position (not shown inthe drawing), it is connected to a cavity which is arranged above thelayer 2 and interacts with a drive element 4.

The functional element 3 of the embodiment shown in FIG. 4 substantiallycorresponds to the functional element 3 from the embodiment shown inFIG. 3, except that the functional element 3 of the embodiment shown inFIG. 4 does not include an opening 30.

The first channel 10 and the second channel 20 and the functionalelement 3 with the valve flap 31′ according to the invention are nowdesigned in such a manner that the valve flap 31′ is arranged at thelocation of the connection between the first channel 10 and the secondchannel 20, in such a manner that the connection between the firstchannel 10 and the second channel 20 is opened or closed by interactionwith a drive element 4 which may be connected upstream and/or downstreamof the valve flap 31′. According to the invention, the first channel 10,the second channel 20 and the valve flap 31′ are designed in such amanner that the first channel 10 has a first width 10 b′, the secondchannel 20 has a second width 20 b′ and the valve flap 31′ has a thirdwidth 31 b′, so that the first width 10 b′<the third width 31 b′, andthe third width 31 b′<the second width 20 b′. Moreover, it is expedientfor the valve flap 31′ to be arranged and formed in such a manner that apump structure with a direction of flow (arrow direction) from the firstchannel 10 to the second channel 20 is provided, it being possible forthe drive element 4 to be connected upstream (4, 132) and/or downstream(132, 4) of the valve flap 31′, as seen in the direction of flow F. Theembodiment described above in accordance with FIG. 4 a provides a pumpstructure (I) according to the invention.

FIG. 5 a shows a partial section through components, arranged on top ofone another, of an apparatus according to the invention in accordancewith a third embodiment of the present invention, and FIGS. 5 b and 5 crespectively show a plan view and a partial plan view of a functionalelement 3 of the third embodiment of the present invention from FIG. 5a.

The third embodiment of the present invention shown in FIG. 5 inprinciple substantially corresponds to the second embodiment of thepresent invention in accordance with FIG. 4, except that the channels 10and 20 and the functional element 3 with the valve flap 31″ are designedand arranged in such a manner as to provide a pump with a direction offlow (arrow direction) from channel 20 to channel 10. In this case, thechannels 10 and 20 expediently have a first width 10 b″ and a secondwidth 20 b″, respectively, and the valve flap 31″ has a third width 31b″, so that the second width 20 b″<the third width 31 b″, and the thirdwidth 31 b″<the first width 10 b″. It will be clear that in the thirdembodiment shown in FIG. 5 a drive element 4 may likewise be connectedupstream (4, 231) and/or downstream (231, 4) of the valve flap 31, asseen in the direction of flow F. The third embodiment of the presentinvention provides a pump structure (II) according to the invention.

For both embodiments of the present invention, namely the embodimentsshown in FIGS. 4 and 5, the angle α expediently includes an angle offrom 5° to 80°, preferably from 15 to 50° and particularlyadvantageously an angle which is such that a tangential transition isprovided between the two channels 10 and 20.

FIG. 6 a diagrammatically depicts the arrangement of an apparatusaccording to the invention in accordance with a fourth embodiment of thepresent invention.

According to the invention, in the fourth embodiment of the presentinvention shown in FIG. 6 a, at least one first valve flap 31′ inaccordance with the pump structure (I) shown in FIG. 4 is connectedupstream of a central drive element 4, as seen in the direction of flow(F), and moreover at least one second valve flap 31″ in accordance withthe pump structure (II) from FIG. 5 is connected downstream of thecentral drive element 4, as seen in the direction of flow F. In thefourth embodiment of the present invention, the pump structure (I) andthe pump structure (II) can in each case be provided by means ofindependent functional elements 3 and their valve flaps 31′ and 31″. Thepump structures (I) and (II) may expediently also be provided by meansof a suitably designed, single-piece functional element 3 with a centralthrough-opening 30 which has a valve flap 31′ connected upstream of itas seen in the direction of flow F, in accordance with the embodimentshown in FIG. 4, and with a valve flap 31″ in accordance with theembodiment shown in FIG. 5 connected downstream of the through-opening30, as seen in the direction of flow F. A functional element 3 accordingto the invention of this type is diagrammatically depicted in FIG. 6 b,which shows a suitable single-piece functional element 3 with a centralcontinuous recess 30, which has a valve flap element 31′ connectedupstream of it as seen in the direction of flow (arrow direction), inaccordance with the embodiment shown in FIG. 4(I), and a valve flap 31″connected downstream of it, as seen in the direction of flow F, inaccordance with the embodiment shown in FIG. 5(II). It is also possiblefor a hole structure 30′, in accordance with the functional element 3shown in FIG. 8, which is described below, to be expediently andadvantageously formed in the functional element 3 instead of the opening30.

FIG. 6 c diagrammatically depicts the arrangement of an apparatusaccording to the invention in accordance with a fifth embodiment of thepresent invention, in which likewise, as in the fourth embodiment of thepresent invention from FIG. 6 a, a first pump structure (I) inaccordance with the embodiment shown in FIG. 4 is connected upstream ofa central drive element 4, as seen in the direction of flow (F), and asecond pump structure (II) in accordance with the embodiment shown inFIG. 5 is connected downstream of the drive element 4, as seen in thedirection of flow F, and in which, moreover, a third pump structure (II)in accordance with the embodiment shown in FIG. 5 is connected upstreamof the central drive element 4, as seen in the direction of flow, and isconnected downstream of the first pump structure (I), as seen in thedirection of flow, and in which, moreover, a fourth pump structure (I)in accordance with the embodiment shown in FIG. 4 is connecteddownstream of the central drive element 4 and is connected upstream ofthe first pump structure (II) in accordance with FIG. 5.

When the fifth embodiment of the present invention shown in FIG. 6 c isin operation, a liquid flows through a channel 10 in the first substratelayer 1, through a pump structure (I) and a channel 20 in the secondsubstrate layer 2, a pump structure (II) and a channel 10 in the firstsubstrate layer 1, a further pump structure (I) and a channel 20 in thesecond substrate layer 2, and finally through a further pump structure(II) and a channel 10 in the first substrate layer 1.

In the fifth embodiment of the present invention shown in FIG. 6 c, thefour pump structures (I) and (II) may be provided by individualfunctional elements 3 which interact with the central drive element 4.The respective valve flaps 31′ and 31″ are expediently and in accordancewith the invention provided by a single-piece functional element 3,which in its central region has a continuous recess 30, in each case twovalve flaps 31, in accordance with the embodiments of the pumpstructures (II) and (I), being connected upstream and downstream of therecess 30, as seen in the direction of flow. FIG. 9 shows a diagrammaticsection through the fifth embodiment of the present invention shown inFIG. 6 c.

An advantageous functional element 3 of this type is diagrammaticallydepicted in FIG. 6 d and in each case comprises valve flaps 31′ and 31″in accordance with the pump structures (I), (II), (I) and (II), whichare connected in series in this order as seen in the direction of flowF, with the central recess 30 arranged between the valve flaps 31′ and31″ of the middle pump structures (II) and (I). It is also possible fora hole structure 30′ in accordance with the functional element 3 shownin FIG. 8, which is described below, to be expediently andadvantageously formed in the functional element 3 instead of the opening30.

FIG. 7 a, by way of example, diagrammatically depicts an apparatusaccording to the invention of the first embodiment of the presentinvention having a channel 10, which is formed in the first substratelayer 1, and a functional element 3 with a continuous recess 30 or ahole structure 30′, with a valve flap 31 connected upstream of it, and asecond substrate layer 2 with a continuous recess 20, which interactswith a cavity 410 formed in a third substrate layer 41. The structureand action of the embodiment shown in FIG. 7 a corresponds to theembodiment shown in FIG. 3, and consequently reference is made at thispoint to the description given in connection with FIG. 3. The layers 1and 2 are arranged above one another, and the functional element 3 isarranged in sandwich fashion between the layers 1 and 2. The fourthlayer 41 with the cavity 410, which comprises a pump chamber, isarranged above the second layer 2 and is covered with a thin glass layer42, above which is arranged a drive element 43 which is provided in asuitable way by means of a piezo actuator 4. It is expedient for theopening 20 in the second layer and the cavity 410 in the layer 41 to beformed and arranged in such a manner that the opening 20 in the secondlayer is arranged at an apex of the cavity 410 in the substrate layer41. This minimizes the penetration of air bubbles into the cavity 410when the present invention is used as a liquid pump.

Forming the cavity 410 in a substrate layer 41, which is arranged abovethe second substrate layer 20, and the advantageous arrangement thereof,have been described by way of example on the basis of the embodimentshown in FIG. 7 a and FIG. 3, and can likewise advantageously be appliedto the other embodiments of the present invention. It will become clearthat the inlet and outlet of channels 10 in the first substrate layermay be arranged in any desired way, for example on opposite sides,parallel or at an angle.

Moreover, it will be clear that the above-described second to fifthembodiments of the present invention can advantageously be combined in acorresponding way with a drive element 43 and the further elements orlayers 4, 41, 410, 42 and 43 in accordance with FIG. 7.

The drive element 4 may expediently be a thin piezo diaphragm.

The present invention may in particular be produced at low cost, even inindustrial series production, in miniaturized form by means ofmicrostructuring techniques.

FIG. 8 diagrammatically depicts an advantageous modification to thesingle-piece functional element 3 according to the invention shown inFIG. 6 d, which expediently comprises a thin plastic film. Thefunctional element 3 also comprises valve flaps 31′ and 31″ inaccordance with the pump structures (I), (II), (I) and (II), which areformed in this order in a plastic film and are arranged in the directionof flow F. A hole structure 30′, which interacts with the cavity 410 ofa pump chamber, is expediently and advantageously formed between themiddle pump structures (II) and (I). The hole structure in this case hasthe effect of a filter which effectively prevents any contaminating ordirt particles contained in a liquid that is to be pumped frompenetrating into the pump chamber 410 and thereby effectively preventsassociated disruptions to the operation of the drive element 4.Consequently, any particles contained in the liquid that is to be pumpedare passed completely through the fluid channel and do not reach thepump chamber, which means that a piezo diaphragm 4 can continue to moveunimpeded. As a result, the demands imposed on the purity of a liquidwhich is to be pumped are advantageously determined solely by thechannel cross section of the channel structures 10 and 20, which may,for example, be approximately 1mm².

The above-described advantageous hole structure 30′ of the functionalelement 3 particularly advantageously interacts with a multiple valvearrangement in accordance with FIG. 6 c, FIGS. 9 and 10, in which caseeven elongate fibrous particles pass through a pump according to theinvention without causing any problems.

FIG. 9 shows a diagrammatic section through an apparatus according tothe invention in accordance with the fifth embodiment of the presentinvention, which has been described in detail above with reference toFIG. 6 c. The fifth embodiment of the invention is particularly suitablefor a single-piece functional element 3 in accordance with FIG. 6 d,which is illustrated by way of example in FIG. 9 and is particularlyadvantageously suitable for a functional element 4 as shown in FIG. 8.

The advantageous series connection of the pump structures (I), (II), (I)and (II) in this order in the direction of flow F, with the respectivevalve flaps 31′ and 31″ and the associated channel structures 10 and 20in the upper substrate layer 1 and lower substrate layer 2 and thecentral drive element 4 arranged between the middle pump structures (II)and (I) and having the central pump chamber promotes a particularlyefficient pump capacity in particular on account of the arrangement atan angle α with in particular a tangential transition between thechannel structures 10 and 20.

FIG. 10 shows an advantageous modification to the fifth embodiment ofthe present invention from FIG. 6 c and FIG. 9, which substantiallycorresponds to the fifth embodiment described above with reference toFIG. 6 c and FIG. 9, except that the transition between the channelstructures 10 and 20 is advantageously designed to be continuous withoutany steps, sharp edges or corners, which significantly increases theefficiency of the pumping capacity still further and also furtherreduces the susceptibility to problems caused by contaminating or dirtparticles to a considerable extent, in particular in combination withthe functional element 3 from FIG. 8 with the hole structure 30′ whichis used advantageously and by way of example here.

In particular the single-piece formation of the functional element 3 andits multi-functional role as a filter and with a plurality ofdifferently designed and similar valve flaps 31 is particularlyadvantageous since it is particularly efficient in terms of performanceand action in particular with suitable channel structures 10 and 20, andmoreover it can be produced and assembled in miniaturized form in asimple and inexpensive way even in large numbers.

A first to fifth embodiment, as described above, of a micropumpaccording to the invention, and in particular the fourth and fifthembodiments of the invention, are particularly suitable for deliveringliquids and gases even in extremely small metered quantities, and givena suitably miniaturized formation may have a particle tolerance up to aparticle diameter of approx. 40 μm. On account of the structure of thefluid channel according to the invention with gradual angles and theintegrated valve flaps, moreover only an extremely minor pressure losscan occur in operation.

Moreover, it will be clear that a micropump according to the inventioncan be used in many sectors, for example for the metering of fluids inchemical, biological and medical analysis, for example for sampling,e.g. in environmental analysis, and also, for example, in the foodindustry, for cooling systems, for transport purposes for example inlubricating systems or for dispensing purposes, etc.

1. An apparatus with channel-like structures for transporting and orstoring a liquid medium, comprising: a first substrate layer (1); and asecond substrate layer (2); and a functional element (3) which isarranged in sandwich fashion between the first substrate layer (1) andthe second substrate layer (2), wherein the channel-like structures areformed in the first substrate layer (1) and the second substrate layer(2); the first substrate layer (1) and second substrate layer (2) arefixedly and permanently joined to one another, and the functionalelement (3) is clamped between the first substrate layer (1) and secondsubstrate layer (2); the functional element (3) is elastic in form; thefirst layer (1) and second layer (2) are rigid in form; the channel-likestructures in the first substrate layer (1) and second substrate layer(2) are at least partially closed off in a fluid-tight manner by meansof the functional element (3); the functional element (3) is formed tobe very much thinner than the first layer (1) and second layer (2); thefunctional element (3) is formed as at least one functional movableelement, in such a manner that the channel-like structures (10, 20) areopened or closed by means of the functional element (3); the functionalelement (3) comprises at least one valve flap (31′,31″); the apparatusfurther comprises a dynamic drive element (4) for altering the volume ofa cavity (410) formed in the apparatus; a first channel (10) is formedin the first layer (1); a second channel (20) is formed in the secondlayer (2), so that a connection is formed between the first channel (10)and the second channel (20); the at least one valve flap (31′,31″) ofthe functional element (3) is arranged in such a manner that theconnection between the first channel (10) and the second channel (20) isopened or closed; the first channel (10) and second channel (20) arearranged parallel to each other; and the connection between the firstchannel (10) and the second channel (20) forms an angle (α) between 15°and 50°, whereby a tangential transition which is formed to becontinuous without any steps, sharp edges or corners between the firstchannel (10) and second channel (20) is provided by means of theconnection between the first channel (10) and second channel (20). 2.The apparatus as claimed in claim 1, wherein said drive element (4) isarranged as a central drive element with the at least one first valveflap (31′) arranged upstream (4, 132) thereof in the direction of flow(F); and the at least one second valve flap (31″) is arranged downstream(231, 4) thereof in the direction of flow (F).
 3. The apparatus asclaimed in claim 2, further comprising a third valve flap (31′) arrangeddownstream (132, 4) of the drive element (4) and upstream of the secondvalve flap (31″), in the direction of flow (F); and a fourth valve flap(31″) arranged upstream (231,4) of the drive element (4) and downstreamof the first valve flap (31′), in the direction of flow (F).
 4. Theapparatus as claimed in claim 3, wherein the first (31′), second (31″),third (31′) and fourth (31″) valve flaps are arranged along thedirection of flow (F) in the functional element (3), and also a recess(30), which is connected to the cavity (410) interacting with the driveelement (4), is formed in the functional element (3) between the second(31″) and third (31′) valve flap.
 5. The apparatus as claimed in claim4, wherein the drive element (4) comprises the cavity (410) which isprovided by means of a further substrate layer (41) having a centralrecess (410) above which a layer (42) with a predetermined rigidity anda piezo element (43) are arranged, and an opening (20) in the secondlayer (2) is arranged at a vertex of the cavity (410) in the substratelayer (41), wherein the functional element (3) is a single-piece elementwhich is formed in a thin plastic film and has the valve flaps (31′,31″) and a central hole structure (30′) which is formed as a filterelement, which interacts with the cavity of a pump chamber.
 6. Theapparatus as claimed in claim 1, wherein the first channel (10) has afirst width (10 b′); the second channel (20) has a second width (20 b′);and a first valve flap (31′) has a third width (31 b′); and thefollowing relationship applies: first width (10 b′) <third width (31 b′)<second width (20 b′); in which, in the direction of flow (132), thedrive element (4) is connected at least one out of upstream (4, 132) anddownstream (132,4) to the first valve flap (31), in the direction offlow (F).
 7. The apparatus as claimed in claim 1, wherein the firstchannel (10) has a first width (10 b″); the second channel (20) has asecond width (20 b″); and a second valve flap (31″) has a third width(31 b″); and the following relationship applies: second width (20 b″)<third width (31 b″) <first width (10 b″); the drive element (4) beingconnected at least one out of upstream (4, 231) and downstream (231, 4)to the second valve flap (31″), in the direction of flow (F).